Hesperian Health Guides
Chapter 67: Artificial Legs
Contents
Below the Knee
The most common leg amputation is below the knee. A leg that has been amputated halfway between the knee and ankle works best for walking with an artificial limb. Here are some examples of artificial limbs, from simple to more complex.
WITH THE KNEE BENT
HAND-HELD POLE LEGS | ‘SAWED-OFF CRUTCH’ LEG |
padding
plastic or wood leg support
canvas or leather sling for knee |
leather or canvas bands
padding
block of wood or piece of plastic curved to fit leg
prop
sawed-off crutch |
WITH THE KNEE STRAIGHT
BAMBOO AND PLASTER LEG | PLASTIC PIPE LEG WITH FOOT |
bamboo
plastic pipe (PVC) |
These limbs are better because the knee has full range of motion. Walking is easier and more natural. However, the person’s weight must be supported evenly over the entire stump, not only at the end of the stump.
Positions for FITTING A LIMB
will only work with a bent-knee limb
knee does not straighten fully
knee straightens completely
Exercises to strengthen and straighten the leg
From the time a leg has been amputated until a limb is fitted, daily exercises are needed to keep the hip and knee muscles strong and to avoid contractures. If weakness and contractures already exist, these should be corrected as much as possible before a limb is fitted. Exercises are discussed in "Prevention of Contractures".
How soon can an artificial limb be fitted?
Children born without a foot or part of a leg (or legs) can be fitted with an artificial limb as early as 10 or 12 months of age.
A child whose foot has been cut off can and should be fitted with a temporary limb as soon as the wound has healed. However, be very careful not to injure or put any pressure on the new scars or end of the stump.
Note:
On some children it may be difficult to fasten the limb firmly to the knee (the bones may not stick out enough). Straps to a waistband and even over the shoulder may be needed.Temporary limbs—when to use them and why
Because a stump usually shrinks and changes shape in the first weeks after a limb is fitted, it is often wise first to fit a low-cost, temporary limb. This is especially true if the amputation is new or the stump is swollen. A better-looking, more permanent limb can be made after 4 to 6 weeks, or when swelling is gone.
Preparing the stump
In the first weeks or months after an amputation, the stump tends to swell up. The swelling may in time lead to a stump which is difficult to fit with an artificial limb. For this reason, it is important to wrap the stump with elastic bandage from the time the leg is cut off until a limb is fitted, or at least until there is no more sign of swelling. Instructions for wrapping the stump are in "Care of the Amputated Limb".
BAD SHAPE | If the stump is swollen or badly shaped, before fitting a limb, wrap it for several days (or weeks) to reduce swelling and improve shape. |
Wrap it to above the knee.
GOOD SHAPE
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Note: When the person is not wearing the artificial leg, he should also wear an elastic bandage to control the stump shape.
The art of limb making
Making artificial limbs that fit and work well is both a science and an art. If possible, try to learn from a skilled limb maker. On-the-job training for even a few days can make a big difference.
Before starting to make an artificial limb, STUDY THE PERSON’S LEG.
A good fit of the socket on the stump and at the knee is one of the most important —and difficult—parts of limb making. It helps to have an understanding of the bones and muscles in the leg.
FRONT VIEW |
Avoid pressure on bony bumps.
Put pressure on kneecap tendon.
Put pressure on muscle areas.
Avoid pressure on shin bone.
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SIDE VIEW |
A GOOD SOCKET
does not press on bony bumps just under the skin.
presses on against muscles
presses in firmly just below the kneecap. (The main weight bearing is here.)
does not press over shin bone. |
leaves enough space at stump tip so that tip will not be injured if the stump settles a little deeper into the socket. |
Before beginning, study the person’s knee and stump carefully. Note the positions of the kneecap, the bony bumps on the sides of the knee, and the shin bone.
distance around knee just below kneecap and every 5 cm. around the stump | length from mid-knee to end of stump | length from mid-knee to heel of complete leg |
length of foot
shoe size
length from mid-knee to heel of good leg |
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Note: For the plaster and bamboo limb, only lengthwise measurements are needed. |
Note: The artificial limb should be the same length or just a little shorter than the other leg. |